BACKGROUND: The main symptoms of gastroparesis are early satiety, nausea, vomiting and bloating. In our daily practice, we observed some patients presenting with concomitant chronic alteration of stool frequency. The present study describes retrospectively the impact of gastric peroral endoscopic myotomy (G-POEM) on patients presenting refractory gastroparesis and concomitant chronic diarrhea or constipation. METHODS: This retrospective study analyzed the clinical course of patients with refractory gastroparesis and concomitant chronic alteration of stool frequency who were consecutively treated with G-POEM between January 2019 and October 2023 in a tertiary referral center. RESULTS: Of 107 patients with refractory gastroparesis treated by G-POEM, 11 (10.3%) patients (mean age 60.4±16.2 years, 64% female) had altered bowel frequency for >6 months without any other underlying disease (diarrhea n=10; constipation n=1). Scintigraphy confirmed delayed gastric emptying in 10/11 (91%) of cases. G-POEM was technically feasible in all patients without adverse events during or after endoscopic treatment. The median follow-up period was 170 days (interquartile range [IQR] 33-1002). In 9/11 (81%) patients, G-POEM achieved clinical success with a mean gastroparesis cardinal symptom index (GCSI) of 3.1 (interquartile range [IQR] 2.7-3.4) before, and 0.9 (IQR 0.7-1.7) after the endoscopic treatment. Normalization of bowel movements after G-POEM was observed in 9/11 (81%) of patients. Two patients had partial symptom improvement (loose bowels, but normal frequency), 1 of them without improvement of GCSI and persistent delayed emptying on scintigraphy. CONCLUSION: Gastroparesis may present with concomitant chronic diarrhea that improves after endoscopic treatment by G-POEM.